1. Field of the Invention
This invention pertains to method and apparatus for positioning and removing down hole packing glands from oil well pumpers.
2. Description of the Prior Art
As is well known, depleted oil wells which no longer have a pressurized flow of oil into the bottom of the well hole can be forced into production by pumping another fluid such as steam or water into an adjacent hole so that the pressure of the fluid fractures the oil bearing strata and forces oil toward the depleted hole. The oil is then brought to the surface, as much as 10,000 feet or more above the bottom of the hole, by a conventional piston pump. The piston pump is reciprocated by 10,000 feet of sucker rod. The sucker rod is coupled to a polish rod which slides in a fixed stuffing tube assemelby that is fixed in the well head.
In order to obtain sufficient stroke of the piston pump and to accommodate the several feet of stretch in the sucker rod during each stroke it is necessary that the sucker rod and thus the polish rod be stroked several feet, preferably about 100 feet. In order to obtain this stroke length a large derrick can be erected over the well head with the polish rod sliding along a packing gland that is located approximately at the ground surface. The cost of such derricks are prohibitive.
A second technique is to put the packing gland some 100 feet down below the ground surface in a hole and then pump with a cable pump of the general configuration such as shown in U.S. Pat. No. 3,640,342 or any other conventional cable pump in which one end of the cable or wire rope is attached to the top of the polish rod and the other end after passing several turns around a powered reversibly rotated drum passes down to a counter weight in a parallel hole. The down hole packing gland, particularly when the packing gland is located 100 feet below the ground surface becomes difficult to inspect, tighten to accommodate wear and stop leakage, or to remove for repair or replacement. One attempt to solve this problem has been to fix the packing gland to the sucker rod and reciprocate the packing gland with the sucker rod during pumping strokes. This has not been a satisfactory solution. Another solution is to threadably connect the packing gland assembly to the surrounding stuffing tube. Because of these packing gland problems the down hole packing gland has not as yet been a satisfactory solution to the generally less expensive technique of pumping deep holes with a cable pumper.